UNDERCARRIAGE AR 3041942 - Caterpillar

TECHNICAL INFORMATION BULLETIN November 24, 2004
Off-Highway Trucks 797 (5YW)
797B (JSM)
Component Code(s) 7340SUBJECT: 797 Cab Glass Can Break in Extreme Cold Weather
PROBLEM:
The front windshield glass for the 797 cab (153-3993 Glass) can break during extremely cold weather (-15°C (5°F) to ?40°C (-40°F). It is believed that the 153-3993 Glass breaks due to a combination of the following three factors:
Extremely cold exterior weather (-15°C (5°F) to ?40°C (-40°F)
Defroster heat being blown directly on the 153-3993 Glass by the 151-5715 Louver Assembly
A rapid increase in cab pressure when the operator closes the cab door
SOLUTION:
Construct a diffuser from PVC pipe as a short-term solution while a new diffuser is being developed. Refer to the procedure below.
Procedure to Construct a Diffuser from a PVC Pipe
Required Parts List
Pt. No. Description Qty
9X-2038 Washer 3
8C-6965 Bolt 3
8T-9014 Silicone Sealant As Required
- 76mm (3") PVC pipe 1.46 meter (57.5") in Length
Cut the PVC pipe in half lengthwise.
In the middle of the top section of the PVC pipe, drill twelve 12mm (.5") holes center spaced at 114mm (4.5") intervals. Ensure that there is distance of 45mm (1.75") between the center of the first hole and the edge of the PVC pipe (see Illustration 1).
Remove the three Torx head bolts on the top of the dash (see Illustration 1).
Install the PVC pipe onto the dash using the 8C-6965 bolts.
Apply a bead of 8T-9014 Silicone Sealant to seal the diffuser to the dashboard.
Illustration 1.
COPYRIGHT 2004 CATERPILLAR
ALL RIGHTS RESERVED